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Silicon nitride/silicon nitride joints with refractory metal (W and Mo) interlayers were vacuum brazed using an active braze, Cu-ABA (Cu-3Si-2Al-2.25Ti, wt%), and two interlayer arrangements in a double-lap offset configuration: SiN/Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/SiN and SiN/Cu-ABA /SiN. Titanium segregated at the SiN/Cu-ABA and Mo/Cu-ABA interfaces, but not at the W/Cu-ABA interface. The room-temperature compression-shear strength values of SiN/Cu-ABA/SiN and SiN/Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/SiN joints were 118±24 MPa and 22±5 MPa, respectively. Elevated-temperature compression tests showed that SiN/Cu-ABA/SiN joints had strength of 31±6 MPa at 1023 K and 17±3 MPa at 1073 K. Likewise, SiN/Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/SiN joints had strength of 19±4 MPa at 1023 K and 13±3 MPa at 1073 K. Knoop microhardness profiles revealed hardness gradients across the joints. The effect of joint microstructure and test configuration on the mechanical behavior is discussed.

This paper describes a search algorithm to find multiple sets of one dimensional unipolar (optical) orthogonal codes characterized by parameters, binary code sequence of length (n bits) and weight w (number of bit 1s in the sequence) as well as auto-correlation and cross-correlation constraint respectively for the codes within a set. For a given code length n and code weight w all possible difference sets, with auto-correlation constraints lying from 1 to w-1 can be designed with distinct code serial number. For given cross-correlation constraint from 1 to w-1 Multiple sets can be searched out of the codes with auto-correlation constraints less than or equal to given auto-correlation constraint using proposed algorithm. The searched multiple sets can be sorted as having number of codes not less than the upper bound of the sets given by Johnson bound. These one dimensional unipolar orthogonal codes have their application in incoherent optical code division multiple access systems.